Table 3.
Characteristics of cardiopulmonary exercise testing.
| Continuous variables, mean (SD) | Total N = 200 |
Without post-COVID-19 syndrome N = 88 |
With post-COVID-19 syndrome N = 112 |
p |
|---|---|---|---|---|
| Peak VO2, mL/min/kg | 27.2 (8.9) | 28.8 (9.6) | 25.8 (8.1) | 0.017 |
| Exercise time, minutes | 9.0 (2.9) | 9.8 (2.6) | 8.4 (3.0) | 0.007 |
| Predicted VO2, % | 91.2 (19.4) | 92.9 (18.7) | 89.7 (19.9) | 0.257 |
| Slope VE/VCO2 | 32.8 (5.7) | 32.5 (5.5) | 33.1 (5.9) | 0.521 |
| Maximum RR | 32.7 (7.2) | 33.5 (5.9) | 32.0 (8.1) | 0.131 |
| RR difference (maximum-basal) | 15.1 (7.3) | 16.3 (6.6) | 14.1 (7.7) | 0.037 |
| Oxygen saturation at maximum effort, % | 97.5 (2.0) | 97.7 (1.9) | 97.4 (2.1) | 0.453 |
| Categorical variables, % | ||||
| RER > 1.1 | 59.5 | 68.2 | 52.7 | 0.03 |
| Dynamic changes of the ST segment | 7.5 | 9.1 | 6.3 | 0.333 |
| Normal oxygen pulse | 89.5 | 89.8 | 89.3 | 0.911 |
| Normal OUES | 44.5 | 45.5 | 43.8 | 0.810 |
| Achieved anaerobic threshold | 60.5 | 72.7 | 50.9 | 0.002 |
| Appeal to the respiratory reserve | 0 | 0 | 0 | |
| Preserved functional capacity | 65.5 | 65.9 | 65.2 | 0.914 |
| Decreased functional capacity | ||||
| Cardiovascular pattern | 61.2 | 58.6 | 63.2 | 0.706 |
| Respiratory pattern | 13.4 | 0 | 23.7 | 0.004 |
| Peripheric pattern | 67.2 | 89.7 | 50.0 | 0.001 |
| Mixed pattern | 41.8 | 48.3 | 36.8 | 0.347 |
| Normal course of BP | 86.0 | 87.5 | 84.8 | 0.588 |
| Exaggerated behavior of BP | 6.5 | 3.4 | 8.9 | 0.116 |
| Symptoms in the test | 35.5 | 13.7 | 52.7 | <0.001 |
| Dyspnea | 92.9 | 75.0 | 96.6 | 0.008 |
| Dizziness | 9.9 | 8.3 | 10.2 | 0.846 |
| Chest pain | 9.9 | 0 | 11.9 | 0.257 |
| Arrhythmias | 21.5 | 19.3 | 23.2 | 0.506 |
| Normal course of heart rate | 95.5 | 93.2 | 97.3 | 0.161 |
BP: blood pressure, OUES: oxygen uptake efficiency slope, RER: respiratory exchange ratio; RR: respiratory rate, SD: standard deviation, VO2: peak oxygen consumption; VE: minute ventilation.